Problem after updating

My website just updated to WordPress 5.0
the problem is that my theme came with a plugin that i have been using to edit pages, which is WPBakery Page Builder. unfortunately, since the update, it seems that the plugin is not working the way its supposed to be. as I used to modify pages using it. now it doesnt appear on the page edit section anymore.
i dont know how to contact the plugin builders maybe you guys can do it.
i want to know if they are aware of the issue and if its gonna be fixed soon? or should i ask for a refund as the main reason of this whole purchase was that and its not working anymore.
Its urgent as im not done building my website.
thank you.

The page I need help with: [log in to see the link]